The struggle in the Tyrol was merely a side issue in the new war with Austria, which was conducted on Napoleon's side with his usual celerity of movement. The days when soldiers are whisked forward at locomotive speed had not yet dawned, yet the French troops made extraordinary progress on foot, and war was barely declared before the army of Napoleon covered Austria. This army was no longer made up solely of Frenchmen. The Confederation of the Rhine practically formed part of Napoleon's empire, and Germans now fought side by side with Frenchmen; Marshal Lefebvre leading the Bavarians, Bernadotte the Saxons, Augereau the men of Baden, Wurtemberg, and Hesse. On the other hand, the Austrians were early in motion, and by the 10th of April the Archduke Charles had crossed the Inn with his army and the King of Bavaria, Napoleon's ally, was in flight from his capital. The quick advance of the Austrians had placed the French army in danger. Spread out over an extent of twenty-five leagues, it ran serious risk of being cut in two by the rapidly marching troops of the Archduke. Napoleon, who reached the front on the 17th, was not slow to perceive the peril and to take steps of prevention. A hasty concentration of his forces was ordered and vigorously begun. "Never was there need for more rapidity of movement than now," he wrote to Massena. "Activity, activity, speed!" [=A Grave Peril Overcome=] Speed was the order of the day. The French generals ably seconded the anxious activity of their chief. The soldiers fairly rushed together. A brief hesitation robbed the Austrians of the advantage which they had hoped to gain. The Archduke Charles, one of the ablest tacticians ever opposed to Napoleon, had the weakness of over-prudence, and caution robbed him of the opportunity given him by the wide dispersion of the French. [=The Battle of Eckmühl and the Capture of Ratisbon=]